suppressed or altered immunity, including susceptibility to viral infections
and increased allergic symptoms

Not all patients will experience all the symptoms, and other symptoms can also occur. Psychological symptoms such as lack of enthusiasm/motivation, cynicism and depersonalisation and withdrawal may also be present, especially if the burnout is due to workplace stress. The physical symptoms of burnout and CFS appear to be identical except in their severity and attribution, with the dividing line between the two diagnoses being set at the point where the symptoms become highly disabling, or whether the cause is thought to be physical (CFS) or psychological (burnout).

The job-demands model of burnout shows that burnout is associated with high
job demands (e.g. pressure at work) and low job resources (e.g. being in
control and having a variety of tasks). Research has shown that job demands
correspond to feelings of exhaustion in burnout out workers.

A study on teachers suffering from burnout found that those teachers
who scored highest on the "Maslach Burnout Inventory" had the lowest levels
of cortisol (the main
stress hormone released by the adrenal glands) throughout the day. The teachers who said they were under
stress but not suffering from burnout had the highest levels of cortisol.
The study also found that those teachers who were highest on the burnout
scales had the highest levels of physical illness complaints. The stress
level did not alter the number of physical complaints among the teachers
who were low on the scale. The factors
associated with high levels of burnout were low job satisfaction, low
perceived levels of support, low perceived levels of being able to cope with
stress and high levels of emotional exhaustion (although this last one could
be a symptom rather than a cause).

This study highlights a number of important findings. First of all, that mental
attitude has a large influence over the ability to handle stress without
suffering from burnout. Second, that people suffering from burnout have higher
levels of physical illness complaints. And third, that low levels of cortisol
(and a suppressed HPA axis) seem to be associated with low stress tolerance
and high levels of burnout.

This particular study also found that stress and burnout are separate variables, i.e.
people can suffer from burnout in the absence of stress, and vice-versa.

Many studies have confirmed that hypocortisolism is associated with burnout,
CFS, fibromyalgia, and childhood abuse victims.

Causes of burnout

Burnout appears to be caused by excessive long-term psychological/physical stress and emotional arousal. It is most
common in service professions such as nursing and teaching, and in jobs
that involve a lot of customer relationships where emotions may need
to be suppressed. The depersonalisation aspect of burnout may
be a protection mechanism designed to protect against the effects of
excessive emotional arousal, by treating the other party as an object
rather than a person.

Stress hormones and burnout

Popular belief is that burnout is the result of excessive stress. This
is the view that Hans Selye took when he presented his General Adaptation
Syndrome theory of stress, which has the following three stages:

[1] The alarm phase at the onset of the stress, which causes the adrenal
cortex to discharge all of its supply of stored hormones into the
blood.
[2] The stage of resistance, where the adrenal cortex enlarges due
to continued stimulation by ACTH, which results in an enhanced ability to
manufacture and secrete higher levels of cortisol. During this stage
there is a greater ability to deal with stress.
[3] The stage of exhaustion, which eventually comes after continued
stress, and results in symptoms similar to the alarm phase. During this
phase the adrenal glands shrink and levels of cortisol fall, resulting
in an inability to cope with stress.

From his results, Selye proposed that many illnesses in humans which are not
obviously caused by an external pathogen, such as liver disease and heart
disease, may be due to the psychological stresses of modern life. He proposed
that the continual stresses of modern life result in the exhaustion phase
of the GAS, which then leads to one of any number of physical illnesses.
This notion has been mostly rejected today due to the advances in
understanding about how the body works, with a greater concentration on the
underlying mechanism of disease. In fact, most of Selye's work seems to have
been forgotten today, and his GAS has largely been rejected. While it is true
that he tried to apply his theories too broadly, there is one very important
fact which he discovered and which is largely ignored today, and that is the
exhaustion phase of the GAS, which appears to correspond with the state of burnout.

Even though early research pointed to a low cortisol state resulting from
excessive stress, this research languished for 10-15 years due to the prevailing wisdom that stress was always associated with high cortisol. However, during recent decades, research has clearly shown that long-term stress can be associated with low cortisol and suppressed HPA axis activation, and this state of low cortisol is associated with CFS, PTSD and burnout. Whether or not the stress causes
hypocortisolism depends on the nature of the threat, the time since onset, and
the person's response to the situation.

Fries et al hypothesize that the hypocortisolism seen in stress-related disorders such as CFS, burnout and PTSD is actually a protective mechanism which has evolved to conserve energy during threats that are beyond the organism's ability to cope. When it appears that it may not be beneficial to continue with the
stressful activity, the brain might have evolved a method of shutting
down the HPA axis to prevent unnecessary expenditure of energy and protect
the body from the damage caused by a long-term stress response.

Autonomic Nervous System

The
autonomic nervous system (ANS) consists of two branches: the
sympathetic and the parasympathetic. The sympathetic nervous system is activated during
any type of physical or mental stress. Effects include: increasing heart rate
and blood pressure, reducing heart rate variability (so that heart rate
doesn't vary much from beat to beat), inhibiting digestion, and diverting blood
from the extremities. The parasympathetic nervous system has the opposite
effect: reducing heart rate, increasing heart rate variability, and facilitating
digestion. The two branches of the ANS are complementary:
when sympathetic activation is high, parasympathetic nervous activation
is reduced, and vice versa. Typically the sympathetic nervous system
is activated during stress, and the parasympathetic nervous system
is more active during the recovery phase after the stress.

Japanese researchers have found that CFS patients tend to have
reduced
parasympathetic activity, and increased
sympathetic activity. They also found that the
same ANS dysfunction is seen in healthy people after engaging in an
acutely fatiguing task, and the lack of parasympathetic activity appears
to correlate to feelings of fatigue. The difference is that in CFS
the ANS dysfunction happens after much lower levels of stress or activity.
Similar ANS dysfunction is seen in burnout and Gulf war syndrome.

The ANS dysfunction seen in burnout and CFS can cause orthostatic intolerance, resulting in
dizziness, fainting and low blood pressure on standing up, along with dysfunction of the gastrointestinal, urinary, temperature regulation, bowel function,
metabolic and hormone systems.

More research is needed to understand what causes the ANS dysfunction.
It may be that the normal "brake" on sympathetic activation in the
prefrontal cortex isn't working properly, so that the sympathetic
nervous system is always hyperactive, resulting in reduced
parasympathetic activation. Alternatively it may be that there is
reduced parasympathetic drive due to fatigue, and the increased
sympathetic activation is compensatory.

Adrenal fatigue

The term "adrenal fatigue" was coined by James Wilson to describe the
hypoadrenalism seen during chronic stress. Wilson proposes that the adrenal
glands become worn out after excessive long-term stress and lose their
ability to produce cortisol. However that does not fit the science.
Although one study found that some CFS patients have shrunken adrenal glands,
most patients have normal adrenal glands which produce normal amounts
of cortisol. Research instead shows that CFS patients have an abnormally low
HPA axis response to stress, as well as an abnormally low cortisol awakening
response (which itself is thought to be a good indication of HPA axis
responsiveness, as waking up is essentially a mild stressor for the HPA axis).
All the research shows that the hypocortisolism is central in nature, i.e.
controlled by the brain, rather than any problem with the adrenal glands
themselves.

Research has shown that fatigue in sports is largely independent of
the state of the muscles themselves (which normally only reach 60% of
capacity during maximum exercise). A large number of factors have been
shown to cause fatigue in athletes, such as core temperature, glycogen levels,
oxygen levels in the brain, thirst, rate of heat accumulation, sleep deprivation, and levels of muscle soreness/fatigue. Psychological factors such as emotional
state, knowledge of the endpoint, other competitors, motivation,
visual feedback, placebos/nocebos, as well as psychological skills training
have also shown to modify athletic performance.

The brain appears to have a "central governor" which puts together
all of these physical and psychological factors in order to generate the
experience of fatigue, in order to protect the body from potential damage
or death due to over-exertion.

Even though the word "emotion" is used, fatigue is somewhat different
to other emotions in that it directly affects the motor cortex, resulting
in great difficulty in the ability to consciously override it. (In fact
it may not be a good idea to override fatigue in the long-term, as that
may lead to overtraining syndrome).

Overtraining syndrome

Athletes who train excessively can sometimes suffer from overtraining
syndrome, with symptoms similar to CFS, as well as similar HPA axis
hypofunction. Overtraining appears to be the result of excessive training
with too little rest over a long period of time, and is thought to be the
result of a combination of physical and psychological stress. It is a particular problem
in ultramarathon runners.

Mental fatigue: unconscious cost-benefit analysis

Research on animals has uncovered what appears to be a unconscious
"cost-benefit analysis" within the brain, which determines whether an activity
is likely to be worth the effort of expending energy. Activity will only
proceed if the benefits outweigh the expenditure in energy. The parts of the
brain which appear to be behind this "cost-benefit analysis" are the
dopaminergic systems, which are involved in reward and goal processing in
the brain.

Boksem suggests that this dopaminergic system is behind feelings of
mental fatigue, and that overriding the signals from this system for a prolonged
period of time results in long-term fatigue, burnout and chronic fatigue.

In the brain, or due to hormones?

Research suggests that both the the brain, and the
HPA axis, may be responsible for the fatigue experienced during burnout and CFS.
Due to the fact that cortisol levels are quite often normal in CFS, it could
be that the abnormalities in the HPA axis are simply a downstream consequence
of the brain shutting off activity. This fatigue
"shutdown" would then affect the motor cortex directly, resulting in great
difficulty in overriding the fatigue, as well as secondarily via the HPA
axis and autonomic nervous system (which are also regulated by the same
parts of the brain).

Relationship to CFS

Burnout and CFS may initially appear to be very different, but closer
investigation shows that they are in fact quite similar. The same
hormonal abnormalities appear in both groups, namely reduced cortisol and
a suppressed HPA axis, as well as similar physical illness complaints.

Also, a significant proportion of CFS patients say that their illness
began during a period of high stress. In some cases this was emotional
stress, but in other cases it was simply a high-pressure job (which in
many cases the person did not find "stressful" in the negative sense).

In fact, all of the known triggers for CFS, such as emotional
stress, negative mental attitude, viral infection, and working in a
high-pressure job, are the same factors which cause burnout. CFS can
best be thought of as a state of long-term burnout which persists
even after the initial stressors have been removed.

DISCLAIMER: Mind-Body-Health.net is an educational resource for chronic fatigue syndrome (CFS), myalgic encephalomyelitis (ME), burnout and related disorders, and is not giving medical advice. Seek advice from a medical practitioner before making any changes to your life, or if you experience worsening symptoms. CFS is a diagnosis of exclusion, so it
is important to rule out other causes for illness.